Black tank valve won't open

[GilnJo]

Hi folks,
Cardinal 3350RL 5er, bought new in April 2018. Have loved it so far, but today leaving the RV park, I couldn't pull the black water valve open. Absolutely no give to it. Pulled as hard as I could; thought I would break it. The two grey valves work fine.

Any suggestions for what the problem may be and how I can repair this? I'm relatively handy, I don't mind cutting open the undercarriage, and I have a trip planned in two weeks.

Thanks for the suggestions everyone!

[mwdilday]

My valve is getting stiff on my 2018 Cedar Creek Champagne 38EL.

[djousma]

Sounds like the cable is seized inside the sheath. I had this happen too. Did you by chance lubricate it with some sort of petroleum lube? If so, the sheath gets soft in reaction. Dealer fixed mine last time. Eventually I replaced all the cable pulls with Barker Auto Drain electric valve actuators.

[bigdaddy1]

I have a 2019 3350RLX that we got this April but I have already begun to spray a small amount of silicone after I pull the valves and push in afterwards.

[changing it up a bit]

I am also an owner of a 3850 Cardinal and have experienced difficulty pulling all the valves.
Here is what I have done to fix the problem;
1.)Remove the access panel on the right of the basement. This will expose the cables.
2.) Remove the cables where they attach to the water manifold panel.
3.) Elevate the cable and squirt WD forty or lube of your choice down the end of the cable. You will need a can that has the straw adapter. Go slow and let it find its way down the cable, keeping it elevated. It may initially be too stuck to move the cable, but if you reattach it to the manifold box and try pulling it, the attaching will give you more leverage. Make sure to support with your hand around the cut out when pulling so you dont break the plastic housing. The cable should move a little. Repeat this process until you get the cable free. I also finished up by creating a guide for my cables by using wire ties to gather them, but dont tighten the wire ties. Just use them as a guide.
This will work just takes patience. If you have further question send me a message and we can discuss further.
Hope this helps

[NMWildcat]

Had the same problem. My cables were longer than they needed to be so they coiled them and routing had some tight angles. Eventually froze and/or broke. Replaced them with correct length cables and routed them much straighter. Haven't had any more problems in the last five years.